Yank a regexp constant out of String#ascii_only?
Shush warning: 'character class has duplicated range'
Shush warning about redefined Net::SMTP#tolsconnect. Implement it as a failsafe wrapper around existing #tlsconnect rather than reimplementing.
Bump to patch version 2.5.4 to distiguish pending release from current release
it's -> its
Add a CommonField#to_s spec to supplement 83b97d2076f53b818373816892c6563927dc45cc
Travis: stop building ree due to unknown errors
Fix mismatched indentation
Fix sendmail delivery to addresses with a leading hyphen
Expose the SMTP envelope From and To addresses and allow them to be overridden.

Envelope From address defaults to return_path || sender || from_addrs.first.
Envelope To address defaults to destinations (to + cc + bcc).

Updates all delivery methods to rely on the SMTP envelope.

References #421 and rails/rails#5985